Process for preparing a chloro-cyanurate complex



United States Patent 3,275,639 PROCESS FOR PREPARING A. CHLQRG- CYANURATE COMPLEX William F. Symes, Webster Groves, Mo, assignor to Monsanto Company, a corporation of Delaware No Drawing. Filed Dec. 16, 1963, Ser. No. 330,616 9 Claims. (Cl. 260-248) The novel chlorocyanurate complex compounds containing potassium and available chlorine, and certain processes for preparing these compounds particularly [(monotrichloro), tetra-(monopotassium dichloro,) ]pen ta-isocyanurate with which the present application is concerned were disclosed in my C0-pSIldiIlg application for letters Patent Serial No. 37,565, filed in the United States Patent Office June 21, 1960, now U.S. Patent 3,150,132. The disclosure contained herein should be taken in conjunction with said US. Patent 3,150,132 and considered as a continuation-in-part thereof.

This invention relates to new chlorocyanuric acid compounds and :to mixtures thereof, which compounds contain potassium and available chlorine, and to methods of preparing such compounds and mixtures thereof. The invention further relates to a new class of compounds which contain potassium and available chlorine and which have unusual resistance to loss of such chlorine. The invention also relates to formulations or compositions containing such compounds which formulations or compositions have improved stability relative to retention of available chlorine, and which are useful, for example, in bleaching, sterilizing, oxidizing and disinfecting operations.

Chattaway and Wadmore in the Journal of the Che-mical Society, vol 81, pages 200202 (1902), point out that trichloroiminocyanuric acid (also known as trichl-orocyanuric acid or trichloroisocyauuric acid) can be prepared by dissolving cyanuric acid in the theoretical quantity of a percent solution of caustic potash and passing a rapid stream of chlorine through the liquid cooled to 0 C. This article further discloses that trichloroiminocyanuric acid separates as a heavy, white crystalline powder which is obtained perfectly pure by washing a few times with water and drying rapidly on a water bath, and when using about 3 grams of cyanuric acid, a yield of more than 90 percent of the theoretical is obtained. If a larger quantity than this be used or the temperature be allowed to rise, the yield is much diminished and the product is more or less impure.

Hardy in U.S. Patent 2,607,738 and Re. 24,412 teaches in column 3, line 71, through column 4, line 8, that trichlorocyanuric acid is prepared by dissolving cyanuric acid in the theoretical quantity of a 5% solution of caustic potash or soda and treating the resulting solution with chlorine until 3 atoms of the alkali have been substituted by chlorine.

It is one object of the present invention to provide novel anhydrous crystalline, potassium-containing chloroisocyanurate complex compounds and mixtures thereof and characterized in having disticnt, available chlorine contents and in having utility in bleaching, sterilizing or disinfecting operations.

It is another object of this invention to provide processes for producing such novel compounds and mixtures thereof.

3,275,63d Patented Sept. 27, 1966 It is a-fur-ther object of this invention to provide formulations and compositions containing these compounds and mixtures thereof which formulations and compositions have exceptional stability with reference to retention of available chlorine, and which are useful, for example for bleaching, sterilizing, or disinfecting purposes.

The present invention is concerned, -in part, with novel, anhydrous, crystalline potassium-containing chloroisocyanurate complex compounds and mixtures thereof which can be obtained, for example, according to one embodiment of this invention by bringing together and reacting trichloroisocyanuric acid and monopotassium dichloroisocyanurate in certain molecular proportions and under conditions which will be described hereinafter. The novel compounds of this invention and mixtures thereof can also be obtained when tripotassium cyanurate is continuously chlorinated under certain specific pH and tem perature conditions which will be described in greater detail hereinafter. One of the compounds of this invention can also be prepared by bringing together and reacting monopotassium dichloroisocyanurate and hydrochloric acid under certain conditions which are set forth in greater detail hereinafter.

One of the novel compounds of this invention is an anhydrous, crystalline solid having a distinct X-ray diffraction pattern and the general formula and is further characterized in that it has an available chlorine content of 66.4%, is soluble in distilled water at 25 C. to an extent of about 2.5% by weight; the pH of a saturated aqueous solution thereof being about 4.3. The above-described compound as prepared in accordance with this invention usually has an available chlorine content in the range of 66% and 67% and decomposes without melting in the range of 260275 C. Crystals of this compound exhibit a distinct elemental analysis, which is described in Table I immediately following Example III. For convenience in description the above-described compound will be designated hereafter either as Compound I or as [(mono-trichlono,) tetra-(monopotassium dichloro,) ]penta-isocyanurate.

X-ray diffraction analysis of Compound I shows a unique X-ray diffraction pattern distinct from the X-ray diffraction patterns of trichloroisocyanuric acid, monopotassium dichloroisocyanurate, or monohydrogen dichloroisocyanuric acid (also known as dichloroisocyanuric acid). The X-ray diffraction pattern of Compound I is shown in Table II, which follows Example III.

The infrared absorption spectrum of Compound I is, in part, common to the infrared absorption spectrum of trichloroisocyanuric acid and such absorption spectrum is also, in part, common to the infrared absorption spectrum of monopotassium dichloroisocyanurate. The infrared absorption spectrum of Compound I substantially demon strates that one moiety of Compound I consists of trichlorocyanuric acid and that another moiety of this novel cyanurate compound is composed of monopotassium dichloroisocyanurate, that is to say, the infrared absorption spectrum of Compound I is substantially identical to a substantially uniform physical mixture of 1 mole of trichloroisocyanuric acid and 4 moles of monopotassium dichloroisocyanurate.

Another new cyanurate compound of this invention is also an anhydrous, crystalline material but has the general formula:

-and is further characterized in that it has an available chlorine content of 75.8%, is soluble in water at 25 C. to an extent of about 1.0% by weight; the pH of an aqueous saturated solution thereof being about 4.1. This compound as prepared in accordance with this invention usually has an available chlorine content of from 75% to 77% and undergoes decrepitation when heated to 170 C.215 C. and decomposes without melting in the region of 260 C.275 C. For convenience in description this compound is hereinafter designated as either Compound II or (trichloro,) (monopotassium dichloro,) di-isocyanurate.

Crystals of Compound II exhibit a distinct elemental analysis, which analysis is compared with the calculated theoretical elemental content in Table I, immediately following Example III.

X-ray diffraction analysis of Compound 11 reveals a unique X-ray diffraction pattern distinct from the X-ray pattern of Compound I hereinbefore described, and also distinct from the X-ray diffraction patterns of trichloroisocyanuric acid, dichloroisocyanuric acid or monopotassium dichloroisocyanurate. This pattern is shown in Table V following Example III.

The infrared absorption spectrum of Compound II like that of Compound I is in part common to the infrared absorption spectrum of trichloroisocyanuric acid and is also in part common to the infrared absorption spectrum of monopotassium dichlorocyanurate. However, the intensity of that part of the infrared absorption spectrum which corresponds to the absorption spectrum of trichloroisocyanuric acid is greater in the Compound H absorption spectrum than in the absorption spectrum of Compound I.

The novel compounds of the present invention may be prepared singly (in pure form) or in the form of mixtures by at least two different methods. One such method comprises bringing together and reacting monopotassium dichloroisocyanurate and trichloroisocyanuric acid in an inert liquid in a reaction zone and isolating the said compound or mixture of compounds therefrom. As will be seen hereinafter, it is possible by varying and controlling the pH of the inert liquid and the molecular ratio between monopotassium dichloroisocyanurate and trichloroisocyanuric acid to prepare either Compound I or Compound II, in pure form, or mixtures of these compounds.

This method of making the novel compounds and mixtures of the novel compounds of this invention, preferably comprises bringing together and reacting in a reaction zone, an aqueous solution containing from about to about 12% by weight of monopotassium dichloroisocyanurate and from about 15% to about 36% by weight of trichloroisocyanuric acid dissolved in an inert organic solvent such as acetone, methyl or ethyl alcohol or the like wherein 15%-36%, more preferably 2025%, by weight of said solution is composed of trichloroisocyanuric acid.

When it is desired to prepare Compound I only, the

amount and concentration of the solutions of monopotassium dichlorocyanurate and trichlorocyanuric acid in the reaction zone should be such that the molecular ratio of monopotassium dichloroisocyanurate to trichloroisocyanuric acid is in excess of 4 to 1 and preferably greater than 5 to 1 and more preferably between 6 to 1 and 8 to 1. Under these conditions essentially pure Compound I separates from the liquid phase of the reaction mixture as an insoluble precipitate which can be separated from the unreacted materials which remain in solution.

When it is desired to produce Compound II, it is generally preferred to bring together and react an aqueous solution of monopotassiurn dichloroisocyanurate containing 5%-12%, more preferably 6%8% by weight of monopotassium dichloroisocyanurate and trichloroisocyanuric acid dissolved in an inert organic solvent such as acetone or methyl or ethyl alcohol wherein 15%-36%, more preferably 30%35% by weight of the solution consists of trichloroisocyanuric acid, the amounts and concentrations of such solutions in the reaction zone being preferably adjusted so that the molecular ratio of monopotassium dichloroisocyanurate to trichloroisocyanuric acid is not more than 1.3 to 1 and is more desirably between 1.15 to l and 1.25 to 1.

It is possible to prepare various mixtures of Compounds I and II by altering the quantities and/or concentrations of the above-described solutions in such a manner as to provide a molecular ratio of monopotassium dichloroisocyanuric acid and trichloroisocyanuric acid in the range of from 3.95:1 to 1.35:1. However, it is preferred to make mixtures of Compounds I and II by bringing together an aqueous solution consisting of from 10% to 25% by weight of monopotassium dichloroisocyanurate and slurry containing from 15 to 60 parts by weight of trichloroisocyanuric acid and from 40 to parts by weight of water; the quantities of the solution and slurry referred to being controlled to provide a molecular ratio Within such range. The particular ratio used will depend on the relative amounts of Compounds I and II which may be desired in the mixture.

In all of the above reactions, which are preferably carried out at a temperature within the range of 5 C.-50 C., a precipitate forms (usually as white, fine, particulate crystals) which can be separated from the bulk of the liquid phase of the reaction mixture by filtration, centrifugation and the like. The precipitate is then preferably dried, although it may be used directly in the wet state. This precipitate is, of course, Compound 1, Compound II or mixtures thereof, depending on the ratio of reactants, etc. as described above. If the product is desired to contain Compound 1, Compound 11 or mixtures thereof, which are free of impurities occasioned by the reaction, the reaction product can be washed with water prior to drying to remove such impurities.

The above-described process can be carried out either as a batch process or as a continuous process but it is preferred to use a continuous process since the latter is more economical.

It has also been found that pure Compound I may be particularly and exclusively prepared in pure form by bringing together and reacting an aqueous solution of potassium dichlorocyanurate and an acid incapable of undergoing an oxidation reduction reaction with monopotassium dichloroisocyanurate and [(monotrichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate. The reaction is carried out in a reaction zone into which the solutions are introduced at rates sufficient to provide and/or maintain a pH within the range of pH 4.6-5.0 and preferably a pH of about 4.8.

A wide variety of acids may be employed in the abovedescribed process and any acid which does not undergo an oxidation reduction reaction with chlorocyanurates particularly monopotassium dichloroisocyanurate and/ or [(mono-trichloro,) tetra (monopotassium dichloro,)] penta-isocyanurate may be suitably employed. Examples of acids which may be used in the above processes include mineral acids such as, for example, hydrochloric, sulfuric, nitric and phosphoric acids and the like and organic acids such as for example acetic, propionic and butyric acids. Particularly advantageous acids which may be employed includes hydrochloric, sulfuric, phosphoric and acetic acids.

The concentration of acid in the aqueous solution referred to above may vary considerably depending upon the particular acid employed but will most advantageously contain from about 2% to about 15% by weight of the acid, the concentration within this range generally depending upon the hydrogen ions present in the particular acid used. Preferably the aqueous solution of acid will contain between about 5% to about 15% by weight of acids such as, for example, hydrochloric, sulfuric, phosphoric and acetic acids.

If less than 2% by weight of acid is employed the volume of solution required will be so large as to be generally impractical in practicing the process. If concentrations greater than 15% by weight of acid are employed difficulty will be encountered in providing and/or maintaining a pH in the desired range.

The amount or volume of aqueous solution of acid employed will vary depending upon the concentration of acid in the solution but is always an amount or volume of solution sufficient to provide a pH (e.g. a reaction pH) within the range of from about 4.6 to 5.0 and is most preferably an amount of acid which will provide and/or maintain a pH of about 4.8.

The amount of potassium dichloroisocynurate in the solution of potassium dichloroisocyanurate employed in the aforedescribed process may vary widely but a solution containing from about 5% to about 9% by weight of potassium dichloroisocyanurate has been found especially desirable. A saturated solution, that is, a solution containing about 9% by weight of potassium dichloroisocyanurate, has been found particularly advantageous in carrying out the processes of this invention.

If a solution containing less than about 5% by weight of potassium dichloroisocyanurate is employed the yield of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate will be significantly lowered.

In accordance with one process of the present invention an aqueous solution containing from about 5%9%, preferably 9% by weight, of monopotassium dichloroisocyanurate is continuously introduced into a reaction zone simultaneously with an aqueous solution of hydrochloric acid containing from about 5% to 15% preferably about 10% by weight of HCl. The solutions (e.g. the aqueous solutions of acid and potassium dichloroisocyanurate) are introduced and subjected to mixing at rates sufiicient to provide or maintain a pH within the range of 4.6 to 5.0 preferably a pH of 4.8, Compound I forms almost immediately as a fine white crystalline precipitate. This precipitate can be allowed to settle to the bottom of the reaction mixture and in any event may be separated from the bulk of the reaction mass by decantation, centrifugation, filtration and the like. The resulting Compound I can then be dried. However, it is preferable to remove reaction impurities by washing the compound with Water prior to use or prior to the drying step.

In accordance with another embodiment of a process of this invention an aqueous solution containing from about 5% to 9% by weight preferably a solution containing about 9% by weight of monopotassium dichloroisocyanurate is continuously introduced into a reaction zone simultaneously with an aqueous solution of a mineral acid such as HCl, H 80 or H PO or an organic acid, preferably an aliphatic organic acid such as acetic, propionic or butyric acid in which the aqueous solution of acid contains from about 2% to preferably from about 5% to 15 by weight of such acids.

The aqueous solutions are introduced preferably simultaneously into the reaction zone and subjected to mixing at rates sufiicient to provide and/or maintain a pH within the range of from about 4.6 to 5.0. By so proceeding [(mono trichloro,) tetra (monopotassium dichloro,)] pentaisocyanurate forms almost immediately as a fine white crystalline precipitate which can be readily separated from the bulk of the aqueous phase of the medium as hereinbefore described.

In the above-described processes the reaction temperature may vary within the range of from just above the freezing point of the aqueous medium to about 65 C. However, the above reactions are preferably carried out at a temperature within the range of from about 5 C. to about 50 C. Although temperatures above 65 C. may sometimes be employed there is danger that a portion of the triazine ring of the potassium dichloroisocyanurate will decompose or partially decompose to form nitrogen trichloride which is hazardous in that it is both toxic and explosive. Generally, when temperatures within the preferred ranges are employed optimum yields of Compound I may be safely and economically obtained. All of the above-described processes can be practiced either as batch or continuous processes but it is preferred to use continuous processes since the latter are more economical.

A further understanding of the products, compositions and processes of the present invention will be obtained from the following specific examples which are intended to illustrate the invention and not to limit the scope thereof parts and percentages being by weight unless otherwise specified.

EXAMPLE I Mono trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate or Compound I.

Sixteen grams of monopotassium dichloroisocyanurate were dissolved in 194 grams of water and placed in a 300 ml. Pyrex beaker. To this solution was added 2.0 grams of trichloroisocyanuric acid dissolved in 8.0 ml. of acetone and the resulting mixture, which mixture had a pH of about 4.9, was stirred at about 300 rpm. with a standard electric stirrer for about ten minutes. A white precipitate, which formed almost immediately, was removed by filter paper filtration in a Biichner funnel. The precipitate, in the form of a filter cake, was successively washed three times with three milliliter increments of water and was aspirated for 5 minutes to remove as much moisture as possible. The filtrate which consisted essentially of water, acetone, and monopotassium dichlorocyanurate was discarded, the filter cake was then dried to constant weight in an oven set at C.

A white dry crystalline solid Weighing 4.94 grams was obtained. An elemental analysis of the crystalline compound is given in Table I which follows Example III.

X-ray diffraction patterns were obtained using the instrument and method described in Phillips Technical Reviews, volume 10, page 1, published in 1948. X-ray diffraction analysis of the above-described white crystalline solid showed a diffraction pattern which was unique and distinct from diffraction patterns shown by either trichloroisocyanuric acid or monopotassium dichloroisocyanurate. A typical diffraction pattern for this novel compound [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate, is shown in Table II following Example III.

The infrared absorption spectrum of the above-described crystalline solid was deter-mined by use of a Beckman IR- 4 Infrared Spectrophotometer according to the method of Stimson et al. in the Journal of the American Chemical Society, volume 74, page 1805 (1952), and will be discussed in greater detail at the end of Example III.

EXAMPLE II [(Mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate or Compound I.

Sixteen grams of monopotassium dichloroisocyanurate were dissolved in 194 grams of water in a 500 ml. Erlenmeyer flask. The resulting 210 grams of solution had a pH of 6.8. To this solution was added a 10% by weight solution of hydrochloric acid in an amount sufiicient to lower the pH from 6.8 to 4.8. As the 10% hydrochloric acid solution was added a fine White crystalline precipitate formed in the solution and settled in the bottom of the Erlenmeyer flask. The crystalline material was filtered, washed and dried to constant Weight at 100 C. as in Example I. The filtrate which contained a mixture of monopotassium dichloroisocyanurate and dichloroisocyanuric acid was discarded.

The yield of white crystalline material was 1.6 grams. An elemental analysis of the crystalline compound is shown in Table 1, following Example III.

X-ray diffraction analyses of the above-described material were obtained as in Example I and the typical diffraction pattern is shown in Table II following Example III.

The infrared absorption spectrum of the above-described crystalline material was determined as in Example I and is discussed after Example III.

EXAMPLE III [(Mono-trichloroQ tetra-(monopotassium dichloro,)] penta-isocyanurate or Compound I.

Approximately 900 ml. of an aqueous slurry having a pH of about 4.5 and containing about 10% by weight of Compound I, prepared according to the method of Example I, was charged to a chlorination vessel, which vessel comprised a jacketed cylindrical glass container having an internal diameter of inches and an internal height of 13 inches which container was supplied with three equidistantly spaced vertical baflles of 1 inch width, spaced radially inward 1 inch from the inside wall of the container. The total capacity of the container was about 3.5 liters of solution. Agitation was provided by a shaft mounted coincident with the vertical axis of the container and provided with a six bladed turbine propeller of 2 inch diameter spaced 2 inches above the inside of the bottom of the container and a second six-bladed turbined propeller of 2 inch diameter spaced 5 inches above the first mentioned propeller. The shaft and propellers were rotated at 2300 revolutions per minute or a propeller tip speed of 1200 feet per minute. The container was also provided with a tube for introducing aqueous tripotassium cyanurate into the bottom of the container beneath the lowest propeller.

The container was also provided with an outlet tube extending vertically downward into the container a distance of inches from the bottom of the container for the removal of reaction products. At such distance the top surface of the 900 ml. of slurry was in contact with the outlet tube and enabled the maintainment of a constant volume of 900 ml.

Four hundred seventy-five grams of potassium hydroxide was dissolved in 4.2 liters of water and the resulting product mixed with 460 grams of cyanuric acid to form an aqueous solution of tripotassium cyanurate. The amount of potassium hydroxide employed was about 0.14 mol in excess of that required to form tripotassium cyanurate and the pH of the cyanurate solution was about 13.7. The resulting solution was filtered and cooled to a temperature of 10 C. This solution of tripotassium cyanurate was then introduced continuously into the aqueous slurry in the container, with agitation, at the speed described above, and concurrently, gaseous chlorine was introduced into the aqueous slurry in an amount and rate sufiicient to maintain the pH at 4.5 and to maintain a constant temperature of 29 C. The volume of the aqueous slurry in the container was maintained constant at 900 ml. by continually pumping a portion of the aqueous slurry, which contained a portion of Compound I, from the vessel through the removal tube. The rate of pumping was a rate sufficient to permit the chlorination of 40 ml. of the slurry per minute while maintaining the volume constant at 900 m1. and the resulting chlorinated slurry, which contained Compound I, was collected in a glass carboy. The

continuous chlorination reaction was continued for 1 hour or until 3300 ml. of the liquid slurry had been chlorinated. The collected chlorinated slurry (3300 ml.) was then filtered through filter paper on a Biichner funnel; the resulting filter cake washed three times with 20 ml. increments of distilled water and dried to constant weight in an even set at 100 C. The product consisted of 330 grams of a white crystalline material with a butt colored tinge which quantity amounted to a product yield of based on the cyanuric acid employed. This product was found to contain 66.8% of available chlorine. A typical elemental analysis of the crystalline compound is shown in Table I below.

X-ray ditfraction patterns of the above-described compound were obtained as described in Example I, a typical pattern being included in Table II. The infrared absorption spectrum of this compound was determined as in Example I and will be discussed below.

The three compounds prepared in Examples I, II and III had identical solubilities in Water, that is to say each was soluble to the extent of about 2.5% by weight in distilled Water at a temperature of about 25 C. and the pH of each of the saturated solutions of these compounds in water was 4.3. Each. of the three compounds decomposed without melting in identical ranges of 260-275 C.

Elemental analyses of the above-described compounds showed that these compounds were substantially identical with respect to carbon, nitrogen, chlorine and potassium content and were in conformance with amounts theoretically calculated for such elements from the hereinbefore referred to formula of Compound I, as shown in the following table.

TABLE I.ELEMENTAL ANALYSES 0F COMPOUND I Found (percent) Calculated Element; Theoretical (percent) Example Example Example I II III 15. 20 15. 40 15. 27 15. 24 17.84 17. 17. 9.3 18. 03 33.19 33.15 33.14 32. 92 Potassium 13. 20 13.35 14. 0t) 13. 30

COMPOUND I [Includes only relative intensities greater than 10%] Anglo (29) Interplanar Relative Spacing Intensity 22. 0 4. 0t 23 22. 4 3. 97 54 4. 9 3. 57 22 27. 15 3. 28 100 23. 2 3. C6 3 29. G5 5. 01 1f) 33. 8 2. G5 60 The available chlorine content of each of the com pounds of the above examples were essentially the same and also essentially the same as the theoretically calculated available chlorine content as shown in the following table.

TABLE III.AVAILABLE CHLORINE-COMPOUND I Available Compound: chlorine (percent) Theoretical (calculated) 66.38 Example I 66.28 Example II 66.30 Example III 66.28

The infrared absorption spectra of the three compounds prepared as described above were substantially alike and essentially the same as the infrared absorption spectrum of a physical admixture of 20% by Weight of dry trichloroisocyanuric acid and 80% by weight of dry monopotassium dichloroisocyanurate demonstrating that each of the above new compounds is composed of two moieties, one containing trichloroisocyanuric acid and one containing monopotassium dichloroisocyanurate in a molecular ratio of 1:4.

Although prepared by distinctly different processes the compounds of Examples I through III have been identified as being chemically identical and conform to the material hereinbefore designated as Compound I The above-described amounts of precursor compounds which were consumed, (that is, tripotassium cyanurate, chlorine, hydrochloric acid and trichloroisocyanuric acid), in the synthesis of the respective compounds of Examples I through III, the identity of the elemental analyses, the available chlorine content, X-ray diffraction patterns, and infrared absorption spectra, made it evident that these products were a single, novel, complex compound having 2 moieties, the one moiety consisting of 4 molecular proportions of monopotassium dichloroisocyanurate and the other moiety consisting of 1 molecular proportion of trichloroisocyanuric acid.

EXAMPLE IV. (MONO-TRICHLORO,) (MONOPO- TASSIUM DICHLORQ) DI-ISOCYANURATE OR COMPOUND II Twelve and eight tenths grams of monopotassium dichloroisocyanurate was dissolved in 187.2 grams of water, placed in a 300 ml. beaker and the resulting product mixed with 10 grams of trichloroisocyanuric acid dissolved in 35 ml. of acetone. The resulting mixture which had a pH of 2.8 was stirred at 300 rpm. with a standard electric stirrer for about 5 minutes. A white precipitate, which formed almost immediately, was removed by filter paper filtration in a Biichner funnel, The precipitate, in the form of a filter cake, was successively washed three times with three milliliter increments of water, and was aspirated for 5 minutes to remove as much moisture as possible. The filtrate was discarded. The filter cake was dried to constant weight in an oven set at 100 C.

A white dry crystalline solid weighing 14.96 grams was obtained, the elemental analyses of which is shown in Table IV, immediately following Example V.

X-ray diffraction analysis showed a diffraction pattern which was unique and distinct from the patterns of the materials of Examples I through III (Compound I), monopotassium dichloroisocyanurate, and trichloroisocyanuric acid. The principal angles and lines of the X-ray diffraction pattern of the second new material (Compound II) are shown in Table V following Example V.

EXAMPLE V. (MONO-TRICHLORO,) (MONOPO- TASSIUM DICHLORO,)DI-ISOCYANURATE OR COMPOUND II An aqueous slurry of Compound II prepared as described in Example IV was placed in the chlorination vessel described in Example III. Tripotassium cyanurate and gaseous chlorine were simultaneously introduced into this slurry of Compound II in the chlorination vessel, otherwise using the procedure of Example III except that the rate at which the chlorine gas was introduced into the reaction vessel was increased to maintain a pH of 3.4 during the chlorination, during which 3000 grams of an aqueous solution containing 13.2% by weight of tripotassium cyanurate was chlorinated in the presence of the slurry of Compound II. The slurry was removed from the reaction vessel, washed and dried as in Example III and a yield of 345 grams of a white crystalline solid was obtained.

Another portion of aqueous slurry of Compound II,

prepared as described in Example IV, was placed in the chlorination vessel and the above-described procedure was repeated except that the rate at which the chlorine gas was introduced into the reaction vessel was increased to maintain a pH of 2.8 during the chlorination procedure which was otherwise the same as the procedure described above. At the end of the process, 347 grams of a white crystalline solid was obtained.

The two materials were identical in appearance and properties and were substantially the same as the material obtained in Example IV. Elemental analyses were run on each material and are shown in Table IV. X-ray diffraction patterns of the two materials were obtained as in Example I, a typical pattern being included in Table V.

Infrared absorption spectra of the above-described crystalline materials, obtained as in Example I, will be described in detail hereinafter.

The compounds prepared in Examples IV and V had identical solubilities in water and decomposed without melting at a temperature range of between 260-275 C. (Table VII). During the melting point determinations, each of the compounds underwent a decrepitation reaction over a temperature range of between 170 C.- 215 C.

The pH of 1% by weight aqueous solution of each of the compounds of Examples IV and V was pH 4.1 at 25 C. and such 1% aqueous solutions represented the identical solubility limit of each of these compounds.

Elemental analyses of the above-described compounds showed these compounds to be different from the compounds of Examples IIII. The compounds of Examples IV and V, however, are substantially the same with respect to carbon, nitrogen, chlorine, and potassium content and are in conformance with those amounts theoretically calculated for the formula (hereinbefore referred to) of Compound 11 as indicated in the following table:

TABLE IV.ELEMENTAL ANALYSES OF COMPOUND II X-ray diffraction analyses of the compounds prepared according to Examples IV and V were also substantially alike. A typical X-ray diffraction pattern of the compounds of the above examples showing the principal angles and lines is as follows.

TABLE V.TYPICAL X-RAY DIFFRAC- TION ANALYSES-COMPOUND II [Includes only relative intensities greater than 10%] Angle 20 Inter-planar Relative Spaclng Intensity The available chlorine content of each of the above compounds of Examples IV and V was substantially identical and also in conformance with the theoretical available chlorine content as shown in the following table.

I1 12 TABLE CHLORINFCOMPOUND II cyanurate and for monopotassium dichloroisocyanurate Available in above described Eixalhliples I-V. d d v en monoso tum 1c oroisocyanunc am is use -%:gg (calculated) i i fi i fff f g g -ig instead of the monopotassiu m salt and reacted with tri- Example IV 5 chloroisocyanur c acid as in Example I, an insoluble Example V PH 35 mater al 18 obtained which was identified as monohyclro- Example V PH 28 7549 gen dichloroisocyanuric acid (also known as (.llClliOI'OlSO u cyanuric acid).

The infrared absorption spectra of the three com- Monosodium dichloroisocyanurate, acidified with hypounds prepared as described above were substantially drochloric acid under the conditions of Example II also alike and essentially the same as the infrared absorption produces dichloroisocyanuric acid. On the other hand spectrum of a substantially uniform physical mixture of when monopotassium dichloroisocyanurate is acidified (as 50% by weight of dry monopotassium dichloroisocyanudescribed in Example II) the new potassium-containing rate and 50% by weight of dry trichloroisocyanuric acid, complex cyanurate, Compound I, is formed. demonstrating that each of the above new compounds is When monosodium dichloroisocyanurate is substituted composed of two moieties, one containing monopotas for monopotassium dichloroisocyanurate and reacted with sium dichloroisocyanurate and another containing trichloapproximately equal molecular proportions of trichloro roisocyanuric acid and that the said moieties are present isocy acid according P' of Example i a mol l r ati f 1;1i th compounds IV, a product is obtained which when dried was iden- Although prepared b diff t processes, h tified as a physical mixture of dichloroisocyanuric acid pounds of Examples IV and V are chemically identical and trichlofoisocfamlllc acidd o for t h complgx compound h i b fo When trisodium cyanurate is chlorinated to pH 2.8, d i d as compound 11 The above described as in the process of Example V (wherein tripotassium amounts of precursor compounds consumed, that is, (tri- Cyanumie was Chlorinated to Pmdml8 the new Potassium potassium cyanurate, trichloroisocyanuric acid and/or containing compiexpyanumm Q p f a P E?- chlorihe) in the synthesis f the compounds f Examples hate is obtained which when dried was identified as in- IV and V; the substantially identical elemental analyses, cnlomlsocyanunc available chlorine content, X-ray diffraction patterns and infrared absorption spectra, make it evident that these EXAMPLE VI-PROCESS FOR PREPARING A products constitute a single novel complex compound MIXTURE OF COMPOUNDS 1 AND H containing two moieties, one moiety consisting of monopotassium dichloroisocyanurate and the other consisting Three grams of trichloroisocyanuric acid were slur" of trichloroisocyanuric acid, the said moieties having a fled in 5 of difimfid Water added t0 3 300 ti f 1;1 beaker containing 135 grams of an aqueous solution con- Although as shown heretofore both Compounds I and mining 64% y Weight of monopotassillm dichloroiso- II can be prepared by bringing together a d ti cyanurate, the resulting molecular ratio of trichloroisomonopotassium dichloroisocyanurate and trichloroisocycyafiuric acid to monopotassium dichlomisocyflnufale ri id, cgmpounds I d 11 diff f h other ing a molecular ratio of about 1:2. The resulting mixand are distinguishable from the aforenoted precursor tuft? Was Stirred in Examplfi The Precipilam which compounds as is shown in Tables VII and VIII. formed was filtered, washed with water, and dried to TABLE VII Water 801- Decomposi- Available Available ubility pH of tion Ternper- Chlorine Chlorine Compound at 25 0. Saturated ature Content Calculated (Percent) Solution Range, 0. Found (Percent) (Percent) Compound I 2. 5 4. 3 260-275 66-67 66. 4 Co pound 11 1. 0 4.1 1 200-275 7547 75. 8 Monopotassium dichlor0isoeyanurate 9. 0 6. 0 220-235 59-60 60. 08 Trichloroisocyanuric Acid. 0. e 3. 0 2 225F230 89-91 91. 54 Dichlor Acid -o 0.8 2. 7 230-235 -71 71. 65

1 Undergoes decrepitation reaction between 170 C.215 C.

Melts with decomposition.

constant weight according to the procedure of Example TABLE VIIL-ELEMENTAL ANALYSES A dry white crystalline solid weighing 6.5 grams and Compound 33 1 2353 gg i fz 0 having an available chlorine content of 71.2% was obp p p tained. An X-ray diffraction analysis, carried out as compound was 1184 33 1329 above-described, showed that the crystalline material was Compound II. 15.30 17.92 37.88 8.34 a mixture of Compound I and Compound II. In other g gf ii ff gf words, the diffraction pattern showed interplanar spacings cyanurqwi 15,25 17378 30,07 1M6 65 and angles common to both Compounds I and II, but fg g f 15 48 18 06 45 77 such pattern in no way resembled the diffraction pattern nichiortis'aa ia'sr's" of trichloroisocyanuric acid or dichloroisocyanuric acid 18-18 21-21 35-83 or monopotassium trichloroisocyanurate.

When monosodium dichloroisocyanurate was substilcalcuated' 7O tuted for monopotassium dichloroisocyanurate under the The discovery of the two new potassium-containing above conditions, a physical mixture of trichloroisocycyanurate compounds which, in part, constitute this inanuric acid and monohydrogen dichloroisocyanuric acid vention was totally unexpected in view of the reactions was formed.

which. occur when trisodium cyanurate or monosodium Mixtures of Compounds I and II in various ratios with dichloroisocyanurate are substituted for tripotassiurn respect to each other can be directly prepared by Example VI to achieve products having an available chlorine content within the ranges of about 67%74% by varying the amounts of trichloroisocyanuric acid and mono potassium dichloroisocyanuric acid using the general procedure of Exampie VI. Mixtures of Compounds I and II can also be made using the chlorination process described in Examples III and V. When such chlorination process is used, mixtures of almost any complementing percentages of Compounds I and II can be prepared by controlling the pH at which the material is chlorinated. The pH should be higher than pH 3.5 and lower than pH 4.2 and any pH in this range can be readily obtained by altering the rates at which chlorine and tripotassium cyanurate are added into a reaction vessel containing a slurry of a complex potassium-containing cyanurate compound of this invention.

Thus if a mixture containing relatively large amounts of Compound I and relatively small amounts of Compound II is desired, the chlorination process should be conducted at a pH range of between 4.1 and 4.4. However, if a mixture containing small amounts of Compound I and larger amounts of Compound 11 is desired, the chlorination process should be carried out at a pH within the range of 3.6 and 3.9.

Although Compounds I and II and mixtures thereof can be prepared by the respective processes described above, it is preferred to prepare Compound I by the chlorination process described in Example III since this continuous process is more economical. Similarly it is preferred to prepare Compound II by the chlorination process described in Example V.

The two anhydrous, crystalline potassium-containing chloroisocyanurate compounds of this invention, either singly, in combination, or when combined with available chlorine containing chlorocyanurates known in the prior art, have utility as active or available chlorine containing materials, in oxidizing, sterilizing, bleaching and sanitizing formulations, such as for example, household laundry compositions, bleaches, scouring powders and sanitizing and dishwashing compositions. Such formulations may contain in addition to the available chlorine containing compounds, neutral and alkaline inorganic salts, for example, detergent builder salts; a minor proportion, usually less than of organic materials such as organic dyes to promote customer acceptance, perfumes, or other odor masking ingredients to make the chlorine odor less noticeable, and surface active agents to promote foaming, wetting, detergency and the like. However, the use of organic compounds in formulations containing high concentrations of available chlorine has been limited in the past because the presence of even small amounts of such organic compounds promote substantial decomposition of the available chlorine compounds resulting in loss of available chlorine and subsequently a reduction in the effectiveness of the formulations.

The above-described novel compounds of the instant invention either singly or as mixtures contain high concentrations of available chlorine and possess a marked degree of stability. The stability toward loss of available chlorine of such novel compounds per se will be readily apparent from the following example.

EXAMPLE VII Samples of powdered (-100I+140) crystalline monopotassium dichloroisocyanurate, monosodium dichloroisocyanurate, dichloroisocyanuric acid, trichlorocyanuric acid, Compound I and Compound II were separately placed in open wide-mouthed bottles in a humidity cabinet set at 105 F. wherein the relative humidity was 90%. After 90 hours the samples were removed to determine the amount of available chlorine that had been lost. The results are set forth in the following Table IX.

14 TABLE IX Loss of available chlorine after 90 Compound: hours (percent) Monopotassium dichloroisocyanurate 1.1 Monosodium dichloroisocyanurate 13.2 Dichloroisocyanuric acid 19.4 Trichloroisocyanuric acid 24.5 Compound I 0.5 Compound II 2.5

As indicated above the novel potassium containing chloroisocyanurate compounds of the present invention are relatively stable in the presence of neutral and alkaline inorganic compounds, particularly inor-ganic salts, which are incapable of undergoing oxidation-reduction reactions with the novel compounds of this invention. Thus a wide variety of such type of inorganic compounds or salts such as alkali and/ or alkaline earth metal phosphates, silicates, carbon-ates, aluminates, sulfates and oxides can be used as builders or inert fillers or abrasives in conjunction with the novel compounds of this invention in oxidizing, sterilizing and bleaching formulations. Also specific alkali metal and/or alkaline earth metal salts such as sodium, potassium, lithium, calcium, barium, aluminum iron and titanium salts of the foregoing acid radicals can be used in combination with the available chlorine compounds of this invention. However, neutral to alkaline alkali metal or alkaline earth metal phosphates, silicates, carbonates, chlorides and sulfates are usually used, wherein the alkali metal is usually the sodium, potassium, or lithium salt and calcium and/ or barium is usually the alkaline earth metal salt.

More specific examples of such inorganic salts are monovalent alkali metal phosphates including orthophosphates such as di and trisodium orthophosphate, alkali metal pyrophosphates such as tetrasodium pyrophosphate and polyphosphates such as sodium tripolyphosphate; metaphosphates such as sodium t-rimeta-, sodium hexametaphosphates and Grahams salts.

Examples of inorganic silicates are meta, ortho, di and tetrasilicates such as the sodium potassium and lithium calcium salts thereof and still other examples are the foregoing metal salts of carbonates, sulfates and chlorides. It is preferred, however, to use the sodium, potassium or calcium salts of the aforedescribed phosphates, silicates, carbonates, sulfates and chlorides.

The inorganic compounds used in combination with the novel potassium containing chlorocyanurate complex compounds of this invention can be either water-soluble or water insoluble, depending upon the particular purpose for which the combination is designed. For example, the water soluble polyphosphates, including pyrophosp-hates are often used as sequestering agents in bleaching formulations; the polyphosphates, silicates, carbonates and sulfates are often as builders, corrosion inhibitors, diluents and the like in detergent formulations. Insoluble compounds such as dicalcium orthophosphate, calcium carbonate, calcium sulfate, titanium dioxide, silica, etc., may be used as abrasive agents as well as natural mineral abrasives such as talc, feldspar, etc., in scouring powders or other grinding or polishing formulations.

The stability with respect to available chlorine of the novel potassium containing chloroisocyanurate complex compounds with the various inorganic compounds or salts mentioned above is illustrated by the following examples:

EXAMPLE VIII A mechanical admixture of 3.3% by weight of potassium dichloroisocyanurate, sodium dichloroisocyanurate, dichloroisocyanuric acid, trichloroisocyanuric acid and Compounds I and II, respectively, in a composition composed of equal parts of potassium chloride, sodium carbonate, sodium metasilicate, sodium t-ripolyphosphate and sodium sulfate were placed in open jars and exposed to a temperature of 90 F. and a relative humidity of 15 for 53 hours. The amount of decomposition as indicated by available chlorine loss is shown in the following table:

TABLE X Loss of available chlorine Compound: after 53 hours (percent) Potassium dichloroisocyanurate 29.6 Sodium dichloroisocyanurate 48.7 Dichloroisocyanuric acid 93.5 Trichloroisocyanuric acid 97.0 CompoundI 17.5 Compound II 39.0

As previously pointed out, the potassium-containing chloroisocyanurate complex compounds of this invention are unique in their excellent stability, with respect to available chlorine, in the presence of organic compounds.

This property is useful in permitting the incorporation of the novel chloroisocyanurate compounds of this invention in formulations containing perfume or odor masking agents such as essential oils, organic sequestering or chelating agents such as the metal salts of ethylenediamine tetra acetic acid; organic dyes and coloring agents such as those described in Venkataraman, Chemistry of Synthetic Dyes, Academic Press, Inc., New York, 1952; organic stain, corrosion, or tarnish inhibitors such as those described in US. Patents 2,618,603 and 3,618,615; and surface active agents such as foaming agents, detergents, emulsifiers and the like.

In this letter category there can be included the anionic surfactants, such as the sulfated and the sulfonated alkyl, aryl, and alkylaryl hydrocarbons set forth in US. Patent 2,846,398, line 54 of column 3 to line 6 of column 5. There can also be included non-ionic surfactants such as those set forth in column of US. Patent 2,846,398 and well known cationic surfactants. Other typical examples of such various categories are described in Schwartz and Perry, Surface Active Agents, Interscience Publishers, New York (1949), and Journal of American Oil Chemists Society, the subject matter of all these publications being incorporated herein by reference.

The preferred organic compounds are those which when incorporated with the novel potassium-containing chloroisocyanurate compounds of this invention in formulations containing 50% or more by weight of the aforedescribed inorganic compounds or salts do not undergo to any appreciable extent an oxidation-reduction reaction with the novel stable chloroisocyanurate compounds and mixtures thereof.

The outstanding stability of the novel compounds of this invention, when used in conjunction with organic and inorganic materials is demonstrated by the following example.

EXAMPLE IX Respective mixtures of 3.0% by weight of potassium dichloroisocyanurate, sodium dichloroisocyanurate, dichloroisocyanuric acid, trichloroisocyanuric acid, Compound I, Compound II and a material containing 97.5 parts by weight of silica and 2.5 parts by weight of the condensation product tridecyl alcohol made by an axe process and about 9 molar proportions of ethylene oxide were placed in an open jar and maintained at a temperature of 90 :F. and a relative humidity of 85% for 24 hours. The excellent stability of the compounds of the instant invention is compared with other chlorocyanurates in Table XI:

TABLE XI Loss of available chlorine Compound: after 24 hours (percent) Potassium dichloroisocyanurate 8.0 Sodium dichloroisocyanurate 10.0 Dichloroisocyanuric acid 14.5 Trichloroisocyanuric acid 16.5 CompoundI 3.9 Compound 11 a- 10.0

1 6 EXAMPLE X Respective mixtures of the 3.0% by weight cyanurate compounds of the preceding examples and a composition containing 97.0% by weight of silica and 3% by weight of sodium dodecylbenzene sulfonate active) were placed in open wide-mouth bottles and exposed to a temperature of F. and a relative humidity of 85% for 53 hours. The results are summarized in the following table.

TABLE XII Loss of available chlorine Compound: after 53 hours (percent) Potassium dichloroisocyanurate 3.4

Sodium dichloroisocyanurate 7.0

Dichloroisocyanuric acid 8.2

Trichloroisocyanuric acid 10.1

Compound I 2.5

Compound II 4.5

The concentration of any of the potassium-containing chloroisocyanurate complex compounds and mixtures thereof of the present invention which may be utilized in a particular formulation will depend largely on the specific use for which the formulation is designed and usually will be in the range of 0.1 to about 98% by weight of the formulation. For example, in strong sterilizing, oxidizing, disinfecting or bleaching compositions, the compounds of this invention may comprise a predominant proportion (e.g. up to 90 or or more) for the formulation. In formulations designed for ultimate consumer use (eg. household formulations such as laundry bleaches, scouring powders and the like) considerably smaller proportions of the novel available chlorine compounds of this invention may be used. For example in a household laundry bleach between about 5% and about 20% by weight of the instant compounds will generally be suitable; with scouring powders from about 20% to as little as 0.05% is often sufficient; with dishwashing compositions between about 1% and 10% is satisfactory.

Although the novel compositions of this invention are remarkably stable in comparison with previously known chlorine compositions containing high concentrations of available chlorine, there is still need for the exercise of some discretion in the formulations of these compounds in conjunction with organic compounds. Thus, by way of example, when the above described inorganic salts are formulated with organic compounds, it will generally be desirable to include in such formulations a dominant proportion; that is, at least 50% by weight of the total formulation of an alkaline or neutral inorganic compound or salt *hereinbefore described to act as an inert diluent for the combination of organic compounds and novel available chlorine containing compound and/or compounds of the present invention. In general it is desirable to have in such composition from about 50% to 99% of inert inorganic diluent, from about 0.05% to about 25% of the above-described organic material and from about 0.05% to about 50% of the novel compounds (singly or in combination) of this invention. For most purposes, however, preferred formulations would contain from about 89%92% of inert inorganic diluent and from about 0.055.0% organic material and from about 0.05- 10% of the novel available chlorine containing compounds of this invention.

As further illustrations of useful bleaching, cleansing and sanitizing compositions containing the novel compounds of this invention, the following typical specific formulations are set forth.

Typical household laundry bleach Weight percent Sodium tripolyphosphate 40 Sodium sulfate 24 Sodium metasilicate 20 Sodium dodecylbenzene sulfonate 5 1 7 Potassium silicate 1 Compound I (may also be Compound II or mixtures of I and II) 10 Typical sanitizing composition Weight percent Sodium sulfate 25 Tetrasodium pyrophosphate 20 Sodium tripolyphosphate 20 Sodium metasilicate 15 Compound I (may also be Compound II or mixtures of I and II) 20 Typical scouring powder Weight percent Silica 90.0 Sodium tripolyphosphate 5.0 Soda ash 2.5 Sodium lauryl sulfate 2.2 Compound I (may also be Compound II or mixtures of I and II) 0.3

Typical dislzwashing formulation (For automatic dishwater) Sodium tripolyphosphate 45 Sodium sulfate 2.3 Sodium metasilicate 2.3 Soda ash 8 Compound I (may also be Compound II or mixtures of I and II) 1 As noted hereinbefore Compound I may be prepared by a process which comprises reacting an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of certain acids. The following Examples XI through XIII exemplify certain preferred embodiments of this process.

EXAMPLE X Sixteen grams of monopotassium dichloroisocyanurate were dissolved in 194 grams of water in a 500 ml. Erlenmeyer flask. The resulting 210 grams of solution had a pH of 6.8. To this solution there was added an aqueous solution containing 6% by weight solution of sulfuric acid in an amount suflicient to lower the pH of the mixture of solution from 6.8 to 4.8. As the 6% sulfuric acid solution was added a fine white precipitate formed in the solution and settled to the bottom of the Erlenmeyer flask. The crystalline material was filtered, washed and dried to constant weight at 100 C. as in Example I. The filtrate which contained a mixture of monopotassium dichloroisocyanurate, dichloroisocyanuric acid and sulfuric acid was discarded, the yield of white crystalline material was 1.5 grams. An elemental analysis of this crystalline compound was substantially the same as that of the crystalline compound, e.g. Compound I, shown in Table I following Example III.

X-ray difiraction analyses of the above-described materials were obtained as described in Example I and a diifraction pattern substantially the same as that shown for Compound I (in Table 11 following Example III) was obtained.

The infrared absorption spectrum of the abovedescribed crystalline material was determined and found to be substantially that obtained for Compound I hereinbefore described.

EXAMPLE XII Thirty-two grams of monopotassium dichloroisocyanurate were dissolved in 320 grams of water in a one liter Erlenmeyer flask. The resulting 420 grams of solution had a pH of 6.81. To this solution there was added with stirring an aqueous solution containing by weight of phosphoric acid in an amount sufiicient to lower the pH from 6.81 to 4.8. As the phosphoric acid solution was added a fine white crystalline precipitate formed in the solution and settled to the bottom of the Erlenmeyer flask. The crystalline material was processed as described in Example XI. The yield of white crystalline material was 3.3 grams. The elemental analysis, X-ray diffraction pattern and infrared absorption spectrum obtained showed that the compound was substantially pure [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate or Compound I.

EXAMPLE XIII One hundred sixty grams of monopotassium dichloroisocyanurate were dissolved in 1940 grams of water in a 5 liter stainless steel vessel. To another container there was added an aqueous solution containing 12% by weight of acetic acid. The vessels containing the respective solutions were provided with outlets by which the flow of the solution from the vessels could be regulated. Into a reaction vessel provided with a mechanical stirrer powered by an electric motor and which also contained electrodes for pH measurement, an over-flow tube, and having a capacity of 600 cc. there was added a 200 ml. portion of the liquid obtained from the reaction process of Example XII. This liquid which had a pH of 4.8 was added to the reaction vessel to provide an aqueous heel. To the reaction vessel there was then added, continuously and at rates sufiicient to provide and maintain the pH at 4.8, the aforementioned solutions of potassium dichloroisocyanurate and acetic acid (as monitored by the pH electrodes). The total rates of addition of these solutions were such that the volume in the reaction vessel was increased at the rate of about 10 cc. per minute. The contents of the reaction vessel were continuously agitated by means of the electric stirrer. As the solutions were progressively added an aqueous slurry comprising solid crystalline Compound I suspended in the aqueous medium was continuously formed. A portion of the slurry was continuously removed from the reaction vessel by means of the over-low tube and fed to a centrifuge from which the solid crystalline Compound I was continuously separated from the bulk of the aqueous phase of the slurry so removed. The reaction was continued for about 3 hours. A yield of 18 grams of [(mono-trichloro,) tetra- (monopotassium dichloro,)] penta-isocyanurate was obtained after the crystalline material was processed as described in Example XI. Elemental analysis, X-ray diffraction patterns and an infrared absorption spectrum were run on the material obtained by the above process. Results of this analysis, diffraction pattern and absorption spectrum showed that the product obtained consisted substantially of pure [(mono-trichloro,) tetra-(mono-potassium dichloro,)] penta-isocyanurate or Compound I.

What is claimed is:

1. A process for preparing crystalline [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocya nurate which comprises the steps of bringing together and reacting in a reaction zone an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of an acid incapable of undergoing an oxidation reduction reaction with said penta-isocyanurate and said monopotassium dichloroisocyanurate in an amount sufiicient to maintain a pH in the range of from about 4.6 to about 5.0 and isolating [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate.

2. A process as in claim 1, wherein the acid is a mineral acid.

3. A process as in claim 1, wherein the acid is a water soluble organic acid.

4. A process for preparing [(mono-trichloro.) tetra- (monopotassium dichloro,)] penta-isocyanurate which comprises the steps of bringing together and reacting in a reaction zone an aqueous solution containing from about 5% to 9% by weight of monopotassium dichloroisocyanurate and an aqueous solution containing from between about 2% to about 15% by weight of an acid incapable of undergoing an oxidation reduction reaction with said penta-isocyanurate and said monopotassium di- 19 chloroisocyanurate in an amount sufficient to provide and maintain a pH in the range of from about 4.6 to about 5.0 and thereafter isolating [(mono-trichloro,) tetra- (monopotassium dichloro,)] penta-isocyanurate.

5. A process for preparing [(mono-trichloro,) tetra- (monopotassium dichloro,)] penta-isocyanurate which comprises the steps of bringing together and reacting in a reaction zone an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of HCl in an amount sufficient to maintain a pH in the range of from about 4.6 to about 5.0 and isolating [(mono-trich1oro,) tetra-(monopotassium dichloro,)] penta-isocyanurate.

6. A process for preparing [(mono-trichloro,) tetra- (monopotassium dichloro,)] penta-isocyanurate which comprises bringing together and reacting in a reaction zone an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of phosphoric acid in an amount sufiicient to maintain a pH in the range of from about 4.6 to about 5.0 and isolating [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate.

7. A process for preparing [(mono-trich1oro,) tetra- (monopotassium dichloro,)] penta-isocyanurate which comprises the steps of bringing together and reacting in a reaction zone an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of sulfuric acid in an amount sufiicient to maintain a pH in the range of from about 4.6 to about 5.0 and isolating [(mono trichloro,) tetra-(monopotassium dichloro,)] 30 penta-isocyanurate.

8. A process for preparing [(mono-trichloro,) tetra- (monopotassium dichloro,)] penta-isocyanurate which comprises the steps of bringing together and reacting in a reaction zone an aqueous solution of monopotassium dichloroisocyanurate and an aqueous solution of acetic acid in an amount sufiicient to maintain a pH in the range of from about 4.6 to about 5.0 and isolating [(mono-trichloro,) :tetra-(monopotassium dichloro,)] penta-isocyanurate.

9. A process for preparing [(mono-trichloro,) tetra- (monopotassiurn dichloro,)] penta-isocyanurate which comprises bringing together and reacting in a reaction zone a saturated solution of monopotassiurn dichloroisocyanurate and an aqueous solution of hydrochloric acid containing from about 5% to 15% by weight of HCl in an amount sufiicient to provide and maintain a pH in the range of about 4.6 to about 5.0 in said zone thereby forming an aqueous slurry consisting of solid [(monotrichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate dispersed in the aqueous phase of said slurry and thereafter separating said [(mono-trichloro,) tetra (monopotassium dichloro,)] penta-isocyanurate from the bulk of the aqueous phase of said slurry.

References Cited by the Examiner UNITED STATES PATENTS 2,913,460 11/1959 Brown et a1 260-248 3,157,649 11/1964 Symes 260248 WALTER A. MODANCE, Primary Examiner.

J. M. FORD, Assistant Examiner. 

1. A PROCESS FOR PREPARING CRYSTALLINE $(MONO-TRICHLORO,) TETRA-(MONOPOSTASSIUM DICHLORO,)$ PENTA-ISOCYANURATE WHICH COMPRISES THE STEPS OF BRINGING TOGETHER AND REACTING IN A REACTION ZONE AN AQUEOUS SOLUTION OF MONOPOTASSIUM DICHLOROISOCYANURATE AND AN AQUEOUS SOLUTION OF AN ACID INCAPABLE OF UNDERGOING AN OXIDATION REDUCTION REACTION WITH SAID PENTA-ISOCYANURATE AND SAID MONOPOTASSIUM DICHLOROISOCYANURATE IN AN AMOUNT SUFFICIENT TO MAINTAIN A PH IN THE RANGE OF FROM ABOUT 4.6 TO ABOUT 5.0 AND ISOLATING $(MONO-TRICHLORO,) TETRA-(MONOPOTASSIUM DICHLORO,)$ PENTA-ISOCYANURATE. 